Coking of tar or pitch



May 8, i934., s. P. MILLER COKING OF TAR OR FITCH Filed Oct. 5, 1929 2 Sheets-Sheet ATTORN EYS May 8, i934, s. P. MILLER COKING OF TAR OR FITCH Filed oct. 5. 1929 2 Sheets-Sheet 2 llNvENToR 5. 7? mzzl/L Patented May 8, 1934 PATENT OFFICE COKING OF TAR OR PITCH' Stuart Parmelee Miller signor to The BarretVColnpany,

, Englewood, N. J., as-

New York,

N. Y., a corporation of New Jersey Application October 5, 1929, Serial No. 397,584

2 Claims. (Cl. ZOB- 28) Ihis invention relates to the coking of tar or pitch in an externally heated still thru which hot combustion gases are passed during the coking operation for further -internally heating the still -and for aiding in the removal from thev still of the vapors which are produced during the coking operation. More particularly the invention relates to coking tar or pitch in a still heated externally by hot combustion gases and the use of the resulting hot combustion gases for further internally heating the still and aiding in the removal of the vapors produced.

According to this invention, tar or pitch resulting from the distillation of tar, is converted to coke in an externally heated still. The material being treated is agitated or tumbled during the coking operation and hot combustion gases are passed thru the still during the coking operation to remove vapors as they are formed. The material being coked is agitated or tumbled so that the vapors formed are released from the coking mass and gases are passed thru the still to remove the vapors from the still as they are formed and prevent or tend to prevent decomposition of the` vapors due to prolonged heating in contact with the heated material or the walls of the still.

The coking is advantageously carried out in a rotating still which contains loose tumbling agitatorsv such as balls or bars or other tumbling means to tumble or agitate the contents of the still. The still isprovided with a gas inlet and a gas and vapor outlet. The latter connects with A a condensing system and an exhauster is used to advantage to cause a circulation o1' gas thru the still. Any suitable means may be employed for heating the still. According to a preferred method of operation hot gases resulting from the combustion of gas or oil or other carbonaceous material are circulated around the still to heat the still, and hot combustion gases passed thru the still to effect rapid removal of oil vapors from the still. The hot combustion gases may consist in whole or in part of waste gases resulting from combustion oi.' fuel used for externally heating the still.

In order to produce clean oils directly from the hot gases and vapors leaving the still, the gases may be cleaned at a high temperature to remove entrained impurities so that on subsequent cooling clean oils will be produced directly from the vapors. The cleaning may be effected in an electrical precipitator adapted to clean such gases at a high temperature. 'I'his precipitator may advantageously beof the Cottrell type in which the ygases pass up thru a plurality of vertical tubeswhich serve as the collecting electrodes thru which discharge electrodes are suspended. The. precipitator may be provided with a jacket thru which a heating medium may be circulated to provide for cleaning of the gases at a high tem 60 v perature and to control the temperature of the gases passing thru the precipitator. Means for ushing the electrodes to keep them free from deposits of tar or pitch may be used to advantage.

Instead of an electrical precipitator a scrubber in which a ne intense spray of hot pitch is sprayed into the gases may be used for removing entrained particles from the hot gases `and vapors. The pitch used for scrubbing the gases may be subsequently fed to the coking apparatus for conversion to coke.

The hot clean gases and vapors leaving the cleaning apparatus may be fractionally cooled so as to produce clean oil fractions directly.

Where tar is'being converted to coke, for exam- 75` ple, a clean creosote oil fraction anda lower boiling carbolic oil fraction may be separately recovered from the gases.

The invention will be further described in con.

nection with the accompanying drawings, but it 30 is intended and is to be understood that the invention is not limited thereto.

Fig. 1 is an elevation of apparatus adapted for carrying` out the invention;

Fig. 2 is a plan view of the apparatus shown in g5 Fig. 1;

Fig. 3 is a section on the line 3 3 and Fig. 4 is a section on the line H4 of Fig. 2.

of Fig. 1;V

In the drawings, 5 indicates the rotating still 90 or retort in which the conversion ot the tar or pitch to coke takes place. The retort 5 is rotated tllruy the gear 6 by means of the motor 7.

lIn the retort are balls or bars or other tumbling pitch g means 8 to tumble or agitate the tar or during the coking operation. The tar or pitch is fed into the retort thru the line 9 and the coke is discharged thru the chute 10. The coke is in a nely divided or powdered condition. It is discharged from the still tlnu the screen or grid 11 into the chute 10. It is discharged from the bottom of the chute 10 thru the gates 12 on to the continuous conveyor 13 and after being quenched by water in the tank 14 is collected in the bin 15.

The still is heated by hot combustion gases resulting from the combustion of fuel supplied to thegburner 20. The hot gases pass over the baies 21 in the nre-box and after passing up around the still 5 pass thru the stack 22 md un the nished coke.

are discharged to the atmosphere. A branch pipe 23 connects with the stack thru the damper 24. By adjustment of this damper and damper 24 inthe stack, and by regulating the amount of gases discharged thru the exhauster 25, a regulated amount of the hot combustion gases is continuously passed thru the still during the coking operation. The hot gases passing thru the still aid in heating the cokingcharge and remove the vapors as they are formed and thus eliminate or tend to prevent excessive decomposition of the vapors by prolonged contact with the hot walls of the still and the contents of the still.

In the arrangement shown in the drawings., the gases and the material being coked pass thru the still in a countercurrent direction.

Pitch fed thru the pipe 9 enters the still where it is thoroughly agitated by the balls 8. The current ot hot combustion gases passing thru the still aids in effecting distillation of the pitch. Vapors of oil distilled from the pitch lare carried from the still by the current of gases passing thru the still. As the.distillation progresses the pitch forms a plastic mass. One or more annular bailles 26 are provided to prevent the initially liquid material from mixing with The material passes thru a plastic statebetween this liquid state and the state of finished coke. As the coke forms it is crushed or powdered by the balls. As it reaches the discharge end of the still it is taken up by the spiral bafiies 27 and discharged thru the openings in the plate 11. The coke is discharged from the still in contact with the hot combustion gases entering the still. The bottom of the chute 10 is sealed in the cooling liquid in the tank 14 to prevent air being drawn up thru the chute by the exhauster 25.

In the drawings means is shown for cleaning the gases and vapors leaving the still prior to cooling them. The gases and vapors pass thru the main 30 which connects the still 5 with the hot pitch scrubber 31. The hot pitch is fed to the scrubber thru the line 32 and the spray nozzle 33 in the tower 34 located on top of the body of the scrubber 31. Bafiling means 35 and 36 are provided to remove entrained particles of spray from the gases to prevent their passing over to the condenser 37.

The pitch fed to/ the still in the tower is 'thrown up into the gases in the scrubber 31 by the rotating roll 38 which is rotated at a high speed by the motor 39. The pitch is discharged from the scrubber thru the trap 40 by the levelling arm 41. The position of the levelling arm is regulated so that a small body of the scrubbing medium is at all times maintained in the body of the scrubber 31 and the level of this body of scrubbing medium is adjusted so that the roll 38 dips into the scrubbing medium to Y only a slight extent. By rotating Athe roll 38 at example, 900-1200 R. P. M., a pitch is thrown up into a speed of, for neintense spray of the the gases. entrained particles from theh gases so that the gases leaving the tower 34 are clean` gases. The entrained particles become incorporated with This scrubs the gases and removesA the pitch and are withdrawn thru the levelling arm 41. According to the drawings, this pitch is fed thru the line 9 to the still" 5 and con-4 verted to coke in the still. I

The clean gases leaving the scrubber are cooled in the condenser 37 and clean oils are there separated from the gases. The resulting gases from which vapors have been condensed are then exhausted from the system thru the exhauster 25 to a stack or other means of disposal, not shown.

Any suitable type of condensing means may be employed. Rectifying means may be used where desirable to produce sharp cut oil fractions. The drawings show a condenser 37 which is a direct condenser adapted to produce two oil cuts. Wa.- ter may be employed as the condensing medium.f This is sprayed into the gases from the line 42. The water and clean oils are drawn off the bottom of the condenser into the decanters 43 and 44. The clean oil fractions may then be sepa-l rately collected in the tanks 45 and 46. One or more oil products may be recovered as desired;

The coke produced is a coke of special quality high in carbon content and low in ash, for example, containing usually not over 1-2% ash and in many cases less than 1%. It is produced continuously incrushed or powdered form and the volatile content of the coke may be regulated within wide limits by regulating the temperature, the quantity of the hot gases passed thru the still and the flow of the gases and material being coked, i. e., counter-current flow or concurrent flow, etc. Cokes .of varying degrees of combustibility may thus readily be produced for the special purposes to which such high grade materials are put.

I claim: l

1. The method'of converting a material of the group consisting of tar and pitch to coke in a still and producing clean oils therefrom, which comprises heating the material in a still to form coke, agitating or tumbling the contents of the still, passing hot combustion gases thru the still, scrubbing the gases and vapors leaving the still with the material to be coked to remove entrained particles from the gases While the gases are at a high temperature, then feeding the scrubbing medium to the still to be converted to coke, and

cooling the cleaned gases to separate clean oils therefrom. y

2. The method of converting a material of the group consisting of tar and pitch to coke in a still and producingclean oils therefrom, which comprises heating the material in a still to form coke, rotating the still and subjecting the contents of the still to the action of loose, tumbling agitators, passing hot combustion gases through the still, scrubbing the gases and vapors leaving the still with the material to be coked, so as to remove entrained particles yfrom the gases while the gases are yet at a high temperature, then feeding the scrubbing medium to the still to be converted to coke, and cooling the cleaned` gases to separate clean oils therefrom.

S. P. MILLER. 

